Is it normal for a 21 month old to suddenly go clingy? During the day, she used to play quite independently while I was doing housework and stuff but for the past week or so she cries and shouts when I go to do anything. When I am in the room, instead of sitting and playing together like we used to, she wants to sit on me and kind of cling to me like a koala bear. There's nothing out of the ordinary that's happened (unless Christmas counts?) and she's not been left with anyone so I don't think it's anything scary or worrying I'll vanish. She doesn't seem ill either.
Is this just something they do?